1. Field of the Invention
This invention relates to the conversion of a recreational vehicle (RV) or camper into a houseboat for use on water. More particularly, the invention relates to the apparatus and methods for loading the RV or camper onto a floatation undercarriage and fixedly securing the RV or camper to the undercarriage.
2. Description of the Prior Art
The conversion of a house trailer into a boat was disclosed by A. A. Haigh, et al. in U.S. Pat. No. 3,265,025, issued Jan. 9, 1966. A house trailer was converted from land-based use to water-based use by backing the trailer onto a boat over its rear, or stern end. To assist in the loading of the trailer onto the boat, a loading ramp could be extended from the rear deck of the boat. If the trailer was loaded from a dock, there was virtually no provision for compensating for any change in water level relative to the loading dock. Alternatively, if the trailer were loaded from the shoreline, the loading of the trailer from the stern of the boat would cause the stern to sink into the soft shoreline making the stern-positioned motors inoperable until the boat had been moved to deeper water.
Two significant shortcomings of the Haigh disclosure were the loading of the trailer from the stern of the boat, and a failure to make any provision to stabilize the boat during the loading of the trailer to prevent the stern from sinking substantially relative to its floating depth.
Subsequent improvements on the Haigh idea recognize the undesirability of loading from the stern and replaced that provision with a bow-loading arrangement. In U.S. Pat. No. 3,731,644, issued May 8, 1973, R. D. Bradt disclosed a catamaran vessel adapted to receive a pickup truck camper body or house trailer by loading over a detachable bow ramp. The vessel can be loaded directly from the shoreline without the use of a loading dock. In U.S. Pat. No. 3,335,437, issued May 15, 1967, A. B. Judkins discloses loading a pickup truck camper from a loading dock over the bow of a boat. U.S. Pat. No. 3,807,338 issued Apr. 30, 1974 to W. C. Shader discloses the conversion of a trailer into a utility boat by loading the trailer from the shoreline over the bow of the floatation portion.
All four of the above references are subject to a single shortcoming. Since the weight of a camper or trailer is concentrated at its axle, the placement of that axle at the bow of the boat on which it is being loaded will produce a substantial and concentrated load at the bow of the boat. Since no provision is made to stabilize the boat portion of these disclosures, the only result can be a substantial drop in the bow end of the boat, together with a significant tilt to the beam of the boat.
In his U.S. Pat. No. 3,745,954 issued July 17, 1973, J. M. A. J. Louet discloses a barge for ferrying a trailer where the barge is supported by a loading dock and loaded from the bow. Although the end of the barge is supported during the loading of the trailer, thereby preventing the end from dipping substantially below its floating position, this arrangement is effective only where the water level of the adjacent body of water never varies. Any body of water subject to tidal variations or subject to a demand usage for flood control, water supply purposes, or hydroelectric generating functions, will experience a significant range in water level. Since each of the above disclosures would be ineffective where the water level in the adjacent body of water varies, their applicability is significantly limited.
The location of the trailer on the supporting boat is quite critical. This results from the need for positioning the center of gravity of the trailer slightly behind the center of gravity of the floatation boat. Unless this orientation between the relative position of the center of gravities can be maintained, it is impossible to give the loaded boat the necessary attitude in the water. In order to obtain stability and control in the water, it is necessary that a boat have a slightly deeper draft at the stern than it does at the bow. Unless some adjustment in the positioning of the trailer on the boat is obtainable, this relative orientation cannot be guaranteed. Additionally, transverse adjustment is desirable to compensate for variations in transverse load distribution in various campers. Both the Bradt patent with its fixed rear pylon 22, and the Shader patent with a supporting ball that is adjustable primarily for height variation and with only moderate longitudinal and no transverse flexibility, could not provide the desired attitude when loaded.
Because it is desirable to load the trailer from the bow end of the boat, it is necessary to make the helm stand, containing the boat controls, either movable or risk interference between the helm stand and the trailer being loaded. The Shader patent makes provision for a hinged helm stand or conning column to lay approximately flat with the deck during the loading and unloading operations. However, since the angle between the deck and the loading ramp is variable, it cannot be guaranteed that an interference situation will not result.